Driving mechanism for motion-picture machines



Sept. 29, 1925.

H. F- HEIDEGGER DRIVING MECHANISM FOR MOTION PICTURE MACHINES Filed Sept. 2, 1922 ll/I45.

Ill 4 anoemtoz Patented Sept. 29, 1925.

UNITED STATES 1,555,370 PATENT OFFICE.

HENRY F. HEIDEGGER, OF BROOKLYN, NEW YORK, ASSIGNOR TO NICHOLAS POWER COMPANY, INC., OF NEW YORK, N. Y.. A CORPORATION 01 DELAWARE.

DRIVING- MECHANISM FOR MOTION-PICTURE Application filed September 2, 1922. Serial 110.5859.

mechanism for use in apparatus for the pro-' jection of motion pictures, and relates particularly to a flexible driving connection between the motor and the driven mechanism of the apparatus.

It is desirable for the satisfactory projection of motion pictures that the film and shutter driving mechanism, commonly driven from an electric motor, be operated at substantially constant speed under all conditions. Variations in the speed of the motor are inevitable, however, due to sudden differences in load caused by sticking of the film, etc. and to external causes beyond the control of the operator, such as changes in the voltage impressed on the driving motor.

It is accordingly'a principal object of the present invention to provide in a motion picture machine a flexible driving connection between the motor and the driven mechvice of thistyp'e consisting o a relatively anism of the apparatus to effect the operation of this mechanism at substantially constant speed at all times regardless of variations in speed of the driving motor.

It is also an object of the invention to provide a device of this type which is entirely automatic in its operation of regulating. for

a constant speed, and which is provided additionally with a manual adjustment to determine the particular speed which is to be maintained. I

It is a still further object to rovide a desmall number of elements and of simple construction, the driving connection being established by means of a friction disc having a replaceable contact surface.

of my invention in the accompanying drawings, in which Figure 1 is an elevat1onal I have illustrated a preferred embodiment view showin the clutch mechanism of the apparatus; ig. 3 isa partial sectional view showing a portion of the mechanism, taken at right angles to'the section shown 1n Fig.

2; and Figure 4 is a detail view showing the construction of a portion of the mechanism.

Referring to'the drawings, particularly to Figure 1, 1 indicates the main frame of the projector which maybe cast as a unit. The

frame 1 is supported at each corner by an inclined leg bracket 7 which is securely bolted to the frame 1 at its u per end and is provided at its lower end witli a socket 8 for receiving the supporting le 9 of the apparatus and permitting in ividual adjustment of each leg. The leg brackets 7 and legs 9 are preferably inclined outwardly as shown for the purpose of providin a large base area so that the individual adpistment of any'leg will not materially shift the center of theapparatus.

Beneath the frame *1 is mounted the driving motor and the friction clutch mechanism indicated at 13 in Figure 1 and shown in detail in Figures 1 and 2. Power from the 30 motoris transmitted to the. clutch mechanism 13 throu'gh-a'suitable belt. The mech-.

anism of the apparatus is operated through a belt driven through the clutch mechanism 13.; i

Referring to Figs. 1 and 2, the driving belt of the machine works over a pulle 22 rotatably mounted upon the through s aft 23 of the clutch mechanism, the ends of the rted in a bracket 24 9 shaft being fixedly sup depending from a suita 1e hanger. The friction disc 25 of the clutch is formed integrally with the pulley 22, or otherwise rigidly attached thereto, and rotates in fixed relation tothe pulley. A facing 26 of suitable material, such as,'for instance, com osition board or leather is preferably fitte to the inner side of the disc 25to'provide a contact surface between the clutch members.

.This facing 26 may be provided'on the co- 9 operatingfriction disc 27 instead of on the disc 25, or a thin facin maybe given each of the discs if desired. to provide only one of the friction discs with a facing of fiber or similar material inasmuch as satisfactory results are obtained in this manner and there is less likelihood of wearing or tearing such as might occur if both discs were so faced. .I- also preferably pro- ,vide' the facing member with a radial slot as prefer, however shown in Figure 4 so that, in case the'contacting faces become covered with oil or otherwise get into such condition that upon I an attempt to separate them a region of par-' tial vacuum is created between them, the discs may nevertheless be moved apart without undue effort.

The inner portion of the shaft 23 is enclosed within a housing 28 and carries a coil spring 29 hearing at its respective ends against the'ballrace 30 and a member or collar 31. A. plurality of rods 32 are attached with uniform spacing around the is free to rotate relative to the shaft 23 but is held in fixed rotative relation with the intermediate member 51 by reason of h the rods 32 and also the rods which extend from a supporting collar 35 through the body portion 33 and into corresponding sockets in member 51. If the coil spring 29 is 'placed under compression, this compression will react against the member 31 and by means of the rods 32 will press the driven friction disc 27 intooperative relation with the disc 25.

For accomplishing the engaging and disengaging of the friction discs there is rovi an actuating mechanism supporte on an extension 36 bolted/to the frame of the apparatus. The upper end of the extension 36 is widened out to form a pair of'walls 37 in which is rotatably mounted a shaft 38 provided at each end with a hand wheel 39 and threaded alon the central portion of its length. The t rea ed rtion lies between the walls 3.7 an t e shaft is restrained from longitudinal movement by means of collars 40 rigidly secured to the shaft and bearing against the outer faces of the walls 37. A member41 is threaded over the shaft between the walls 37 and is engagement by means of a lever 44 sup ed at one end-.by the shaft 45 of the cl restrained from rotation so that by'roftating the shaft .38 the' member 41 may be made to move longitudinally of the. shaft over the entire distance betweenthe walls. The movement of the member 41 is utilizedthrough the medium of a bell crank lever 43. The movement of the bell crank lever 43 is utilized in bringing the friction discs into utch shifting mechanism and attached at its otherend to the lower extremit of a connectmg rod 46 whose u per en is secured to the free arm of the 11 crank lever 43.

block 47 w ich engages with the ball race 30 on the shaft 23 and moves it longitudinally of its shaft whenever shaft 45is rotated. The lever arm 44 ma be rigidly connected to. the shaft 45 in w ich case operation of the adjusting mechanism which I causes the outer end of the lever to be raised or lowered, will efi'ect a corresponding rotation of the shaft 45. and a consequent com ression or elongation of the spring 29, us to the movement of the hall race 30 along its shaft. For the purpose of giving a wider range of adjustment, however, the lever 44 is preferabl left free to rotate. about the shaft 45 an an additional member 48 is secured rigidly to the shaft and is engaged by a set screw 49 threaded in a boss 50 cast on the side of the lever 44. Thus if the outer end of the lever 44 is lifted, the set screw 49 will engage with the member 48 and cause shaft 45 to rotate, moving the friction discs into engagement. Adjustment of the set screw, owever, permits movement of the lever about its shaft. This, together with the ad justment afforded by the bell crank lever 43, gives a wide range of adjustment and spring 29 may be compressed to any desired de cc to suit conditions of operation.

0 attain substantially constant speed of the driven elements an automatic regulating device is provided to vary the driving connection established between the friction discs as the speed of the driving disc changes. The member 51 is fitted over the shaft 23 and assembled between the member 31 and the member 33, the rods 32 passing longitudinally through it. Member 51 is free to rotate about the shaft, but is held by the rods 32 and 35 in fixed rotative relation with the body portion 33, the rods35 being two in number passing through the member 33 at diametrically opposite points The longitudinal movement of the member 51 relative to the body 33 is limited by rods 35 contactin'g with the bottomsof their sockets. Spaced equally around the periphe of the member 51 and rojecting radia ly outwardly is "a plurality of brackets or extensions 52 in each of which is pivoteda metal block 53, the pivots being nearer one end of the block than the other. Under the influence of rotation .the blocks 53 will tend to spread outwardly and will consequently move about their pivots. The shorter ends ofthesmblocksare provided with inwardly extending fingers 54, whichflwhen the heavy ends of the blocks are swung outwardly, en-- gage behind the. flange 55 formed at the inner end ofthe'body member 33 and-tend to move the body member longitudinally of the shaft, thus decreasing the pressure between the friction discs 25 and 27. I

In adjusting the apparatus the compression of the coil spring 29 will be regulated through the hand wheels 39 or set screw 45) such that the proper speed will automatically be maintained. If the spring is subjected to a high compression the speed at which the centrifugally operated blocks 53 will affect the driving engagement between the friction discs will be correspondingly high. By properly adjusting the compression of the spring the members 53 may be made to decrease the pressure exerted between the friction discs at any speed desired. Such adjustment may conveniently be made while the apparatus is in operation by merely turning one or the other of the hand wheels 39, two of these wheels being provided so that the adjustment may be made with equal facility from either vside of the machine.

I have found that an apparatus equipped with my improvement will regulate for substantially constant speed rcgardles of variations in speed of the driving motor. If the driving motor speeds up the members will move outwardly and slightly decrease the pressure exerted between the friction discs, thus allowing a slight amount of slip between them and yet not completely disrupting the driving engagement or moving any of the elements through an appreciable distance. \Vhen the speed of the driven member begins to decrease slightly the members will press against the flange 55 with less force and allow the spring to force the friction discs more securely into driving engagement.

\Vhile I i have illustrated and described preferred embodiments of my invention, it is understood that the details of construction may be varied within the full scope of the appended claims.

I claim: I

1. Driving mechanism for motion picture projectors comprising a friction driving disc, a cooperating disc driven therefrom and movable longitudinally relative to said driving disc, means rotatable with said driven disc fornormally pressing the engag ing faces of said discs together, centrifugally actuated means for regulating the pressure between said discs, :1. carrier for said centrifugally actuated means and said I pressing means movable longitudinally with respect to both the driving disc and the driven disc and means for limiting the longitudinal movement of said carrier without restricting the free longitudinal movement of said driven disc.

2. Driving mechanism for motion picture projectors comprising a friction driving disc, a cooperating disc driven therefrom and movable longitudinally relative to said driving disc, means rotatable with said driven discfor normally pressing the engaging faces of said discs together, a shaft carrying both the driving disc and the driven disc, centrifugally actuated means carried by said shaft and rotatable and slidable thereon for varying the pressure between said discs upon variations in the rotative speed of said driven disc, said means comprising a plurality of actuating members and acarrier for said actuating members, fixed rotatively with respect to said driven disc and spacing rods associated with said carrying member and traversing said driven disc without attachment thereto for determining the longitudinal spacing of said carrying member and said driven disc.

3. Drivingmechanism for motion picture projectors comprising a shaft fixedly mounted 1n the frame of the projector, cooperating friction driving and driven members mounted for independent rotation and independent relative slidable movement upon said shaft, centrifugally actuated means for varying the pressure between said discs upon variations in the rotative speed of said driven disc, comprising a lurality of actuating members mounted or independent rotatable and slidable movement on said shaft, a spring for normally pressing the engaging faces of said'discs together, rods traversing said carrier and engaging said driven disc for transmitting the pressure of said spring to the driven member and maintaining said carrier and said driven disk in fixed rotative relation. but permitting relative slidable movement between said parts and rods traversing said driven disc and engaging said carrier for limiting the longitudinal movement. of said carrier, but permitting relative longitudinal movement of the carrier, the driven disc and the driving disc.

In testimony whereof I affix my signature.

HENRY F. HEIDEGGER. 

